Glass Fiber From an HVAC System

Fibers in a moving air stream collect particles from that air stream that are about the same diameter
or smaller than the diameter of the fiber. There are a couple of different micro-environments that can
expose glass fiber to moving air streams indoors. The most obvious is the heating, ventilation, and cooling
system (HVAC system). Another source is glass fiber insulated walls with perforations. All walls have per-
forations at electrical outlets, switches, or along the baseboard of the wall. Normal "breathing" of the
wall creates the air movement and over time the glass fibers at those perforations will become coated with
these small particles. The types of particles on the surface of the fiber can be used to determine if the
fiber was exposed to outside air, inside air, filtered air, or recycled air with reasonably high probability
using assembalge analysis.